epítopos

An epitope, also known as an antigenic determinant, is the specific portion of an antigen that is recognized by a particular antibody or B-cell receptor. Antigens are molecules that can elicit an immune response, and they are often large and complex. However, the immune system doesn't bind to the entire antigen molecule; instead, it targets specific, small regions on its surface. These are the epitopes.

Epitopes can be made up of a linear sequence of amino acids (a linear epitope) or a three-dimensional arrangement of amino acids brought together by the folding of a protein (a conformational epitope). Antibodies can bind to either type, though conformational epitopes are generally more common targets for antibodies.

The interaction between an epitope and an antibody or B-cell receptor is highly specific, much like a lock and key. This specificity is crucial for the immune system to distinguish between foreign invaders and the body's own tissues, preventing autoimmune reactions. Understanding epitopes is fundamental in fields like immunology, vaccinology, and diagnostics, as it allows for the development of targeted therapies and diagnostic tools that can specifically recognize and interact with disease-causing agents or other molecules of interest.